Characterizing Dietary and Physical Activity Patterns in Relation to Hydration Among Pre-Adolescent Children

Objectives The aim of this study was to characterize food and fluid consumption as well as and physical activity patterns in children in relation to ad libitum hydration. Methods Child participants aged 9–11 years (N = 55, 28 females) reported beverage consumption with a 7-day fluid diary. Overall diet was reported using a 7-day diet record and analyses were run using the Nutritional Data System for Research (NDSR). Physical activity was assessed with hip worn accelerometers (Actigraph wGT3x+, Pensacola, FL) over 7 days and aerobic fitness was measured with a VO2 max test. Body composition was assessed with dual energy x-ray absorptiometry (DXA). Urine was collected over a 24hr period and was analyzed separately with a refractometer and freezing point depression for specific gravity (USG) and osmolality (UOsm), respectively. Results Children reported ad libitum consumption of 1645 ± 856 mL of total fluid per day, which was comprised of 37% plain water and 12% milk. The remaining 51% was composed of juice, carbonated, sports, fruit, and caffeinated beverages. Mean 24 h UOsm was 780 ± 250 mOsm/kg and USG was 1.019 ± 0.007. Activity data showed participants spent 52 minutes of MVPA/day. Partial correlations, adjusting for VO2 max, % body fat, sex, energy intake, and accelerometer wear time per day, revealed relationships between plain water consumption and USG (r = −0.32, P = 0.05). USG was related to sedentary activity/day (r = −0.37, P = 0.03); however, there were no other relationships between physical activity and urine hydration markers or plain water intake (all p's > 0.05). Total healthy eating index score (HEI) was not related to plain water intake (r = 0.16, P = 0.34) but trended with UOsm (r = −0.30, P = 0.07). Further, UOsm was inversely correlated with the specific HEI subcomponents of higher vegetable (Rho = −0.32, P = 0.02) and lower saturated fat (Rho = −0.28, P = 0.04) consumption. Conclusions Water consumption in children was below recommendations, and fruit drinks, carbonated drinks, and juice comprised a significant proportion of beverages consumed. Higher water consumption was correlated with lower urine concentration, providing additional support for the importance of water for hydration in children. Finally, hydration was not related to weight status, % body fat, or habitual physical activity. Funding Sources Danone Research, Palaiseau, France.